JP2973783B2 - Vehicle front wheel steering angle control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel steering angle control device for controlling a front wheel steering angle of a vehicle while detecting and feeding back a lateral motion such as a skid speed of the vehicle.

[0002]

2. Description of the Related Art Conventionally, as a steering control technique which contributes to steering control of a vehicle while feeding back the skidding speed of the vehicle, as described in Japanese Patent Application Laid-Open No. Sho 62-247971, a rearward control of the vehicle in accordance with the skidding speed is known. There is a known wheel steering control.

However, conventionally, the following problems cannot be completely eliminated because the fed back skid speed contributes to the steering angle control of the rear wheels.

[0004]

That is, in the two-wheel vehicle model shown in FIG. 6, the equation of motion of the vehicle is expressed as follows. However, [delta] _f is the front wheel steering angle in FIG. 6, [delta] _r is the rear wheel steering angle, a is the distance between the front and center of gravity, b between the rear wheels, the center of gravity distance, V is the vehicle speed, (d / dt) y is Skidding speed, (d
/ Dt) φ indicates the yaw rate.

[Number 1] m [V (d / dt) φ + (d 2 / dt 2) y ] = C _f {δ _f - [a (d / dt) φ + (d / dt) y ] / V} + C _r { δ _r − [(d / dt) y−b (d / dt) φ] / V｝ + F ₀ (1)

[Number 2] ^{I (d 2 / dt 2)} φ = aC f {δ f - [a (d / dt) φ + (d / dt) y ] _{/ V} -bC r {δ r} - [(d / dt ) y-b (d / dt ) φ ] _{/ V} + M 0 ···· (} 2) where: m · · · vehicle mass C _f · · · wheel cornering power C _r · · · rear wheel cornering power I · ..Yaw inertia moment F _0: disturbance lateral force M _0: disturbance moment

From the above equations (1) and (2), the yaw motion (d
/ Dt) φ, (d ² / dt ² ) φ, and sideslip motions (d / dt) y, (d ² / dt ² ) y, and disturbance F
The relationship between ₀ and M ₀ can be written as:

M (d ² / dt ² ) y = − [mV + (aC _f −bC _r ) / V] (d / dt) φ − [(C _f + C _r ) / V] (d / dt) y _{+ C f δ f + C r} δ r + F 0 ··· (3)

I (d ² / dt ² ) φ = − [(a ² C _f −b ² C _r ) / V] (d / dt) φ] − [(aC _f −bC _r ) / V] ( _{d / dt) y + aC f} δ f + bC r δ r + M 0 ··· (4)

The eigensystem of the vehicle represented by the equations (3) and (4) can be schematically represented as shown in FIG. 7, where S is a differential operator d / dt. As is clear from FIG. 7, in a general vehicle, the yaw rate (d /
When dt) φ occurs, the block C among the blocks A, B, C, and D generates a skid speed (d / dt) y,
When the skid speed (d / dt) y occurs, the block D has a unique system in which the yaw rate (d / dt) φ is generated. Therefore, these yaw rates (d / dt) φ
And the sideslip speed (d / dt) y influence each other by interfering with each other using the functions represented by the blocks C and D.

[0007] This is because, without considering such vehicle-specific system, simply by feeding back the side-slip velocity (d / dt) y, than determining the rear wheel steering angle [delta] _r based on this, for example, by a proportional constant Q _r the rear wheel steering angle δ _r δ _r = Q _r ·
Explaining the case of determining as (d / dt) y, the above equations (3) and (4) are changed to the following equations (5) and (6), causing the following problem.

M (d ² / dt ² ) y = − {mV + [(aC _f −bC _r ) / V]} (d / dt) φ + ｛− [(C _f + C _r ) / V] + Q _{r C r} (d / dt)} y + C f δ f + F 0 ··· (5)

[6] ^{I (d 2 / dt 2)} φ = - _{^{[(a 2 C f -b 2 C}} r) / V ] (d / dt) φ + {[(aC _f -bC _r) / V] - _{bQ r C r} (d /} dt) y + aC f δ f + M 0 ··· (6)

As is clear from the equations (5) and (6), when the skid speed (d / dt) y is fed back for controlling the rear wheel steering angle, blocks B and D in FIG. 7 change. When the block D changes so as to increase, the component of the yaw rate (d / dt) φ caused by the side slip speed (d / dt) y increases via the block D, and the desired operation effect by rear wheel steering is obtained. Cannot be performed sufficiently.

Therefore, it is necessary to reduce the mutual interference between the yaw rate (d / dt) φ and the sideslip speed (d / dt) y. To achieve this object, ｛[ (aC _f -bC _r) / V] -bQ
_It is necessary to reduce _r C _r 、, in which case Q _r becomes a positive value. Thus, in the above expression (5) under such Q _r, side slip velocity (d / dt) y autonomously inhibit factor {- _{[(C f + C r) /} V ] + Q _r C _r} is , The absolute value is reduced, and the skid speed (d / d
When t) y occurs, the side slip acceleration (d ² / dt ² ) y for suppressing it becomes small, and it is inevitable that the convergence deteriorates. However, the above coefficient ｛−
[(C _f + C _r ) / V] + Q _r C _rよ う
That the Q _r, if you increase as _{Q r ≧ (C f + C} r) / C r V, there is a possibility that diverges.

When the skid speed (d / dt) y is fed back for rear wheel steering angle control, the mutual interference between the yaw rate (d / dt) φ and the skid speed (d / dt) y is reduced as described above. In this case, the problem of convergence deterioration or divergence cannot be avoided.

According to the present invention, the feedback control of the steering system based on the lateral motion such as the side slip speed is performed, and the control object is the front wheel instead of the rear wheel, and the front wheel steering angle is feedback-controlled based on the lateral motion. By doing so, even if the steering angle control for reducing the mutual interference between the yaw rate and the side slip speed is performed, the convergence is not deteriorated or the divergence problem is not caused, and the front wheel steering angle is reduced. It is an object of the present invention to determine the limit of the feedback control coefficient so that the feedback control does not become unstable, and to solve the above problem without causing the control instability.

[0012]

SUMMARY OF THE INVENTION For this purpose, a front wheel steering angle control device for a vehicle according to the present invention detects a physical quantity related to a lateral motion of a vehicle and steers the detected physical quantity. In the vehicle contributing to the above control, first, the front wheel steering angle is determined by feedback control using a negative control coefficient according to the physical quantity.

The vehicle front wheel steering angle control device of the present invention further comprises:
A value obtained from a control function that cancels the vehicle-specific influence function that determines the amount of vehicle yaw motion generated by the lateral motion is used as the upper limit of the absolute value of the control coefficient.

Further, at a low vehicle speed lower than the set vehicle speed, the difference between the front wheel steering angle corresponding to the steering wheel operation amount and the front wheel steering angle controlled by the above is reduced or eliminated. It is better to limit.

Further, in the feedback of the lateral motion, the deviation between the lateral motion target value obtained by the calculation based on the target vehicle model and the physical quantity relating to the detected lateral motion is determined as described in claim 3. Feedback,
Preferably, the front wheel steering angle is determined based on this.

[0016]

According to the structure of the first aspect, the front wheel steering angle control device comprises:
A physical quantity related to the lateral motion of the vehicle is detected, and the front wheel steering angle is determined by feedback control using a negative control coefficient.

In the feedback control of the vehicle steering system based on the lateral motion, since the control object is the front wheel, the control angle of the feedback control is set to a negative value, and the steering angle for reducing the mutual interference between the yaw motion and the lateral motion is reduced. Even if the control is performed, the convergence does not deteriorate or the divergence does not occur.

In the first aspect of the present invention, the negative control coefficient is further limited as follows.
That is, a value obtained from a control function that cancels the vehicle-specific influence function that determines the amount of vehicle yaw motion generated by the lateral motion is set as the upper limit of the absolute value of the control coefficient. Here, if the absolute value of the control coefficient is too large, the front wheel steering angle control enters an unstable range. In the present invention, however, such a situation occurs because the negative control coefficient is limited as described above. Can be prevented, and the above-described problem can be solved while preventing the front wheel steering angle control from becoming unstable.

When the front wheel steering angle is limited so as to reduce or eliminate the difference between the front wheel steering angle and the front wheel steering angle corresponding to the steering wheel operation amount at a low vehicle speed less than the set vehicle speed, Benefits are obtained. That is, the front wheel steering angle control as described above is required at medium and high vehicle speeds, and at a low vehicle speed, the difference from the front wheel main steering angle corresponding to the steering wheel operation amount rather affects the steering force etc. The limitation of the front wheel steering angle in the low vehicle speed range can reduce or eliminate the uncomfortable feeling.

In the feedback of the detected physical quantity relating to the lateral motion, instead of feeding back the detected physical quantity as it is, a lateral motion target value is obtained by calculation based on a target vehicle model. If the deviation between the physical quantities relating to the detected lateral motion is fed back and the front wheel steering angle is determined based on the feedback, the feedback control of the front wheel steering angle is performed only when the deviation is present. Separation from the forward control becomes possible, and it is possible to achieve both suppression of vehicle behavior against disturbance and high response to steering input.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram of a vehicle steering system showing one embodiment of a front wheel steering angle control device of the present invention. 1 is the left and right front wheels,
Reference numeral 2 denotes left and right rear wheels, and a front wheel 1 is mainly steered (a steering angle θ / N when a steering gear ratio is N) by a steering wheel 3 via a steering gear 4, and a steering gear 4 is driven by an actuator 5. the by displacing in the vehicle width direction, [delta] _F enables assist steering direction or steering back direction increases changes as. The rear wheel 2 is steerable to as [delta] _r by the actuator 6.

The front wheel assist steering actuator 5
Is normally supported by the built-in spring at the neutral position to maintain the front wheel auxiliary steering angle δ _F at 0, and when pressure is applied to one of the cylinder chambers, the front wheel 1 is shifted δ in the corresponding direction.
_It is assumed that only _{F is used for} auxiliary steering. The rear-wheel steering actuator 6 also, when being elastically supported in a neutral position by a normally built springs, the rear wheel steering angle [delta] _r kept at 0, the apply pressure to one of the cylinder chamber, the rear wheels 2 is steered by δ _{r in the} corresponding direction.

The supply of pressure to the cylinder chambers of the actuators 5 and 6 is performed by respective solenoid valves 7 and 8, so that the solenoid valves 7 and 8 are supplied with liquid from a pressure source consisting of a pump 9 and a diverter valve 10. The pressure circuits 11 and 12 are connected, and the common drain circuit 13 is connected.

The solenoid valve 7 is a three-position valve.
In a normal state where both L and 7R are turned off, the cylinder chambers on both sides of the actuator 5 are drained from the circuit 13 and the front wheel auxiliary steering angle δ
_{When F is set} to 0 and the solenoid 7L is turned on, a pressure corresponding to the amount of current supplied is supplied from the circuit 11 to the corresponding cylinder chamber of the actuator 5, and the actuator 5 is caused to stroke in the corresponding direction by the corresponding distance, whereby the front wheel When the solenoid 1R is turned ON, the pressure corresponding to the amount of current is supplied to the corresponding cylinder chamber of the actuator 5 to cause the actuator 5 to stroke in the corresponding direction by the corresponding distance. Thus, the front wheels 1 are assisted to the right by the corresponding steering angle.

The solenoid valve 8 is also a three-position valve, and the solenoid 8
L, to 0 to rear wheel steering angle [delta] _r bilateral cylinder chamber to drain from the circuit 13 of the actuator 6 in a normal state for both the OFF and 8R, the pressure corresponding to the energization amount when turning ON the solenoid 8L from the circuit 12 actuator 6, the actuator 6 is stroked by a corresponding distance in a corresponding direction, whereby the rear wheel 2 is steered to the left by a corresponding steering angle. The supplied pressure is supplied to a corresponding cylinder chamber of the actuator 6 to cause the actuator 6 to stroke in a corresponding direction by a corresponding distance, thereby steering the rear wheel 2 to the right by a corresponding steering angle.

Solenoid valve solenoids 7L, 7R, 8L, 8R
ON, OFF and the amount of electricity, that is, the front wheel auxiliary steering angle and the rear wheel steering angle are performed by the controller 14,
For this reason, a signal from a steering angle sensor 15 for detecting the steering angle θ of the steering wheel 3 and a signal from a vehicle speed sensor 16 for detecting the vehicle speed V are input to the controller 14, and the vehicle side skid speed (d / dt) A signal from the side slip speed sensor 17 for detecting y and a signal from the stroke sensor 18 for detecting the stroke of the actuator 6, that is, the actual rear wheel steering angle, are input.

The controller 14 on the basis of these input information, calculates a front wheel auxiliary steering angle [delta] _F and the rear wheel steering angle [delta] _r, the solenoid 7L of the solenoid valves 7 and 8 so that these operational steering angle is achieved, 7R, The actuators 5 and 6 are stroked by controlling ON and OFF of 8L and 8R and controlling the amount of current. However, when the steering angle control of the rear wheels 2 shall perform the control of the electromagnetic valve 8 so that the deviation between the actual steering angle detected by the stroke sensor 18 and computing a steering angle [delta] _r is zero.

Here, as is well known, the front wheel assist steering angle δ _F is basically determined as δ _F1 represented by the following equation.

Δ _F1 = K _f · θ + T _f · (d / dt) θ (7) where K _f : a proportional constant according to the vehicle speed V T _f : a differential constant according to the vehicle speed V That is, in the steering transition period when the steering amount θ is small and the steering speed (d / dt) θ is fast, the response is enhanced by using the differential term T _f · (d / dt) θ in the above equation,
In the steering period when the steering amount θ is large and the steering speed (d / dt) θ is low, the stability is improved by making the proportional term K _f · θ in the above equation effective.

[0029] In this context, on the basis of the rear wheel steering angle [delta] _r that same idea,

Δ _r = K _r · θ + T _r · (d / dt) θ (8) where K _r : proportional constant according to vehicle speed V _Tr : differential constant according to vehicle speed V It shall be.

By the way, in the present embodiment, the front wheel auxiliary steering angle is the side slip speed (d / dt) detected by the sensor 17.
feeding back the y, and adopting the front wheel auxiliary steering angle [delta] _F represented by the following equation in consideration of this.

Δ _F = K _f · θ + T _f · (d / dt) θ + Q _f · (d / dt) y (9) where Q _f : feedback coefficient (a simple proportional constant may be used, (It may have dynamic characteristics.)

[0031] In accordance front wheel auxiliary steering angle [delta] _F calculation and output does this by executing a control program of FIG. That is, first, the vehicle speed V and the steering angle θ are read, and then the control constants K _f , T _f , and Q _f are calculated, and the side slip speed (d / dt) y is read. Then, a front wheel auxiliary steering angle [delta] _F by the operation of the equation (9), to command it to the electromagnetic valve 7.

FIG. 3 shows the steering system of the vehicle based on the above-described front wheel assist steering angle control and rear wheel steering angle control, and the portion surrounded by the dashed line in FIG.
This is an eigensystem of the same vehicle as shown in FIG. Also, in this figure, _Af indicates the control function of the front wheel assist steering in the above equation (7), _Ar indicates the control function of the rear wheel steering in the above equation (8), and θ / N bypasses the control function _Af. Indicates the front wheel main steering angle of the steering gear 4. The front wheel steering angle [delta] _f is expressed by the sum value of the Shukaji angle theta / N, and an auxiliary steering angle [delta] _F1, and passed through a feedback factor _{Q f Q f · (d /} dt) y.

[0033] In this example the way, it determines the feedback factor Q _f in as follows. Side slip speed (d / d
t) y is fed back and, based on this, the front wheel steering angle δ _f
Is determined by the control function Q _{f as} δ _f = Q _f · (d / dt) y, the above equations (3) and (4) are rewritten as the following equations, respectively.

M (d ² / dt ² ) y = [− mV− (aC _f −bC _r ) / V] (d / dt) φ + [− (C _f + C _r ) / V + C _f Q _f ] ( _{d / dt) y + C r} δ r + F 0 ··· (10)

I (d ² / dt ² ) φ = − [(a ² C _f −b ² C _r ) / V] (d / dt) φ + [(bC _r −aC _f ) / V + aC _f Q _f ] _{(d / dt) y -bC r} δ r + M 0 ··· (11)

[0034] These (10) and (11) As is apparent from the equation, if feedback control of the front wheel steering angle [delta] _f based on side-slip velocity (d / dt) y, depending on the control function Q _f, (10 ) And (11) the sideslip speed (d
/ Dt) y [− (C _f + C _r ) / V + C _f
Q _f] and _{[(bC r -aC f) / V} + aC f Q f ]
Changes. Incidentally, the former coefficient is a coefficient for autonomously suppressing the lateral force applied to the vehicle, and the latter coefficient is that the side slip speed (d / dt) y is the yaw rate (d / dt) φ and the yaw angular acceleration (d ² / dt). ² ) A coefficient that affects φ, and therefore the former coefficient is negative in view of the original purpose of reducing the mutual interference between the yaw rate (d / dt) φ and the side slip speed (d / dt) y. It is preferable to increase the coefficient in the negative direction (therefore, increase the control function _Qf in the negative direction) and decrease the latter coefficient (to 0).

From these viewpoints, the yaw rate (d / dt)
The conditions of φ and side-slip velocity (d / dt) control functions eliminate the mutual interference between y Q _f is firstly possible greater in the negative direction, it is then that limit optimal control function Q _OP
Since this is a function for setting the latter coefficient to 0,

Q _OP = − (bC _r −aC _f ) / (V · aC _f ) (12) This optimal control function Q _OP
Is, for example, a = 1.25 m, b = 1.35 m, C _f = 1
0,000kgf / rad, C _r = 15,000kgf
/ Rad, the function as a function of the vehicle speed V is as shown by the solid line in FIG.

As is apparent from FIG. 4, the optimal control function (optimal feedback coefficient) Q _OP is a negative value in the entire vehicle speed range, and the absolute value decreases as the vehicle speed V increases.
The change rate with respect to the vehicle speed is large in the low vehicle speed range.

[0037] Here, consider the case of a large negative direction than the optimum value Q _OP feedback factor Q _f, this case is the side slip velocity (d / dt) y occurs in the negative, the yaw rate (d / Dt) φ and yaw angular acceleration (d
² / dt ² ) φ occurs positively, and consequently, the skid acceleration (d ² / dt ² ) y occurs negatively, and the skid speed (d) increases more and more.
/ Dt) y becomes negative, and becomes an unstable region that causes the vehicle's butt swing phenomenon. Conversely, the feedback factor Q _f, although it is the condition is negative, when the absolute value than the optimum value Q _OP is a small, enters a stable region. Therefore, the feedback factor Q _f, the value in the area indicated by hatching in FIG. 4, i.e.

## EQU13 ## It is preferable to determine such that the following condition is satisfied: Q _f ≧ − (bC _r −aC _f ) / (V · aC _f ) (13)

By the way, the front wheel assist steering is required when the vehicle is running at a medium to high vehicle speed. At a low vehicle speed, the difference between the front wheel assist steering amount, that is, the front wheel steering angle θ / N corresponding to the steering wheel operation, is determined by the steering force and the like. Influence and make you feel uncomfortable. For this reason, in the low vehicle speed range, as shown by the broken line in FIG. 4, the front wheel assist steering is limited or prohibited by reducing or setting the feedback coefficient _Qf to 0, thereby eliminating the above-mentioned uncomfortable feeling. Good.

In the above example, as is clear from FIG. 3, since the side slip speed (d / dt) y is always fed back as it is, if the vehicle behavior with respect to the disturbance is to be surely suppressed, the response to the steering input θ also becomes dull. I can't escape. FIG. 5 shows an example in which this problem can be solved. In this example, a vehicle reference model exhibiting a desired vehicle behavior is prepared, and based on this, the target side slip speed (d / dt) is calculated from the front wheel main steering angle. ) Find y _m . Is then calculated and the target side slip velocity (d / dt) y _m, the deviation △ (d / dt) y between the measured side-slip velocity (d / dt) y detected by the sensor 17, front wheel steering angle in accordance with this Is feedback-controlled.

In the configuration of this embodiment, the feedforward control and the feedback control are completely separated from each other. In addition to this, while keeping the response to the steering input high, it is possible to suppress the vehicle behavior against the disturbance separately. It can be assured. Further, the tuning of the feed forward and the tuning of the feedback can be performed independently, and the efficiency at the development stage can be improved. Furthermore, even if the steering angle sensor 15 or the skid speed sensor 17 fails and information from them cannot be obtained, at least one of the feedforward control and the feedback control can be secured, which is a great advantage in safety. .

The target value of the feedforward control is defined as yaw rate / steering wheel steering angle = Gφ
Set the primary delay of (1 + τS). In this case, the feedforward control function A _f is

A _f = [{MIV ² S ² + [IV (C _f + C _r ) + mV (a ² C _f + b ² C _r )]] S + L ² C _f C _r + MV ² (bC _r −a C _f )} _{/ C f V (LC r +} maVS) become (1 + .tau.S)] Gφ-1 ··· (14). The side slip speed (d / dt) y at this time is represented by the following equation:

Equation 15] (d / dt) y = { (IVS + LC r b-maV 2) / (LC r + maVS)} × {Gφ / (1 + τS)} × {θ / N} ··· (15) Figure this 5 in advance, and the model is set. Incidentally, the feedback coefficient Q _f determined as in the example described above. In this case, the front wheel steering angle δ _F
Is determined by δ _F = A _f (θ / N) + Q _f Δ (d / dt) y.

[0042] In any of the above embodiments, the feedback factor Q _f of side-slip velocity was proportional coefficient, may of course be added to lead element for compensating the delay of the actuator system.

[0043]

As described above, the front wheel steering angle control device for a vehicle according to the present invention performs feedback control of a vehicle steering system based on lateral motion, and the control target is a front wheel. Even if the control coefficient is set to a negative value and the steering angle control for reducing the mutual interference between the yaw motion and the lateral motion is performed, the problem of the convergence deterioration or the divergence does not occur.

The apparatus for controlling the steering angle of a front wheel of a vehicle according to the present invention further comprises a control function for canceling a vehicle-specific influence function which determines the amount of vehicle yaw caused by lateral movement. Since the obtained value is used as the upper limit value of the absolute value of the control coefficient, it is possible to prevent the absolute value of the control coefficient from being too large to prevent the front wheel steering angle control from entering an unstable range. The solution to the above problem can be realized without stabilization.

According to a second aspect of the present invention, the front wheel steering angle is limited so that the difference between the front wheel steering angle and the front wheel steering angle corresponding to the steering wheel operation amount is reduced at a low vehicle speed less than the set vehicle speed. In such a case, it is not necessary to control the front wheel steering angle to reduce the mutual interference between the yaw rate and the lateral movement, but rather, the difference between the front wheel main steering angle corresponding to the steering wheel operation amount affects the steering force and the like, and makes the driver feel uncomfortable. In a low vehicle speed range, the uncomfortable feeling can be reduced or eliminated.

When the detected physical quantity relating to the lateral motion is fed back, instead of feeding back the detected physical quantity as it is, a lateral motion target value is obtained by calculation based on the target vehicle model. When the detected deviation between the physical quantities related to the lateral motion is fed back and the front wheel steering angle is determined based on this, the feedback control is performed only when the deviation is present, and the feedback control and the feedforward control are separated. It is possible to achieve both suppression of vehicle behavior against disturbance and high response to steering input.

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram of a steering system showing an embodiment of a front wheel steering angle control device for a vehicle according to the present invention.

FIG. 2 is a flowchart showing a front wheel steering angle control program executed by the controller of the example.

FIG. 3 is a system diagram of front and rear wheel steering control in the same example.

FIG. 4 is a preferable region diagram of a feedback coefficient used in the example.

FIG. 5 is a control system diagram similar to FIG. 3, showing another example of the front wheel steering angle control device according to the present invention.

FIG. 6 is a two-wheel model diagram of a vehicle.

FIG. 7 is a system diagram showing a vehicle-specific system.

[Explanation of symbols]

 Reference Signs List 1 front wheel 2 rear wheel 3 steering wheel 4 steering gear 5 front wheel auxiliary steering actuator 6 rear wheel steering actuator 7 solenoid valve 8 solenoid valve 10 shunt valve 14 controller 15 steering angle sensor 16 vehicle speed sensor 17 skid speed sensor 18 stroke sensor

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-257773 (JP, A) JP-A-5-77751 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) B62D 6/00

Claims (3)

(57) [Claims] 1. Detecting a physical quantity related to a lateral motion of a vehicle,
A vehicle contributing to the control of steering using the detected physical quantity, wherein a front wheel steering angle is determined by feedback control using a negative control coefficient according to the physical quantity, and an amount of vehicle yaw motion generated by the lateral motion is generated. A front wheel steering angle control device for a vehicle, characterized in that a value obtained from a control function that cancels the vehicle-specific influence function that determines the maximum value is used as an upper limit value of the absolute value of the control coefficient. 2. The vehicle according to claim 1, wherein at a low vehicle speed lower than the set vehicle speed, the front wheel steering angle is limited so that a difference from a steering angle corresponding to a steering wheel operation amount is reduced or eliminated. Front wheel steering angle control device. 3. The front wheels according to claim 1, wherein feedback control is performed based on a deviation between a target lateral motion value of the vehicle obtained by calculation based on a target vehicle model and the detected physical quantity related to the lateral motion. A front wheel steering angle control device for a vehicle, which is configured to determine a steering angle.